1. Field of the Invention
The present invention relates to a waterproof connector to be used in a humid place or in a place which could be flooded with water.
2. Description of the Prior Art
A conventional waterproof connector of this type, as disclosed in Japanese Patent Publication No. 62-241277 of Showa, is shown in FIG. 5. A housing 21 having a rectangular recessed portion 21a is stored in a case 22 with one end thereof opened, and a plurality of terminal insertion holes 23 are provided in the bottom surface of the housing 21 within the recessed portion 21a. A plate-shaped waterproof rubber plug 25 including a plurality of insertion holes 24 respectively corresponding to the terminal insertion holes 23 and contactable closely with the respective terminal surfaces, is fitted into the recessed portion 21a.
In the bottom surface of the recessed portion 21a, there are provided a plurality of projections 26 respectively between the terminal insertion holes 23. In the surface of the rubber plug 25 facing the bottom surface of the recessed portion 21a, as shown in FIG. 6, there are formed fitting holes 27 which are respectively engageable with the projections 26.
After the projections 26 are respectively engaged with the fitting holes 27 to fit the rubber plug 25 into the recessed portion 21a, terminals A are inserted respectively through the insertion holes 24 into the terminal insertion holes 23 to thereby assemble the waterproof connector.
In the above-mentioned arrangement, the engaging structure (consisting of the projections 26 and fitting holes 27) is provided between the housing 21 and rubber plug 25, so that the insertion holes 24 of the rubber plug 25 are arranged so as to have a shape which allows them to be in close contact with the terminals A. In other words, as shown in FIG. 7, if a plurality of terminals A are inserted sequentially through the insertion holes 24 of the rubber plug 25 into the terminal insertion holes 23, then terminal insertion forces F are applied onto the rubber plug 25 to deform the rubber plug 25 elastically. As a result, the centers of the insertion holes 24 into which the terminals have not been inserted yet are shifted from the centers of the terminal insertion holes 23. This increases the difficulty of the terminal insertion operation. The engaging structure prevents such shift of the centers of the insertion holes.
However, in the above-mentioned conventional structure, since the inherently contractible rubber plug is designed to prevent shifting of the positions of its terminals, in a multi-electrode connector including a very large number of terminals A, as shown in FIG. 7, as the terminals A are inserted one after another, the terminal insertion forces F act on the fitting holes 27 of the rubber plug 25 adjoining the terminals A to expand the fitting holes 27. This gradually increases the elastic deformation of the rubber plug 25, and thereby shifts the positions of the insertion holes 24 from those of the terminal insertion holes 23. That is, the shift preventing effect of the multi-electrode connector is lessened.